This invention relates to apparatus for rapidly and accurately attaching and detaching stationary and movable mold halves to and from stationary and movable die plates, respectively, of a die casting machine, a plastic injection molding machine, or a press machine.
According to a known method, the stationary and movable mold halves have been attached to the stationary and movable die plates by using a crane or a hoist in such a manner that the mold halves lifted by the crane are lowered between the stationary and movable die plates so that the center of a sleeve of each mold half aligns with substantially the central portion of the width of the injection molding machine and the position of the lifted and lowered mold half is determined by finely adjusting the height of the crane. After the center of the sleeve of the stationary or movable mold half has been made to coincide with the center of a plunger sleeve of the stationary or movable die plate of the injection molding machine, the mold half is manually pushed into the plunger sleeve and the mold half is then clamped to the die plate by using well known mold clamping means.
The detachment of the stationary or movable mold half from the stationary or movable die plate has been performed by the steps of combining the stationary and movable mold halves, lifting the combined mold halves by using the crane or hoist, removing the mold clamping means to separate both mold halves, and manually removing the stationary and movable mold halves from the plunger sleeves of the respective die plate. The mold halves are carried to the outside of the injection molding machine by using the crane.
In the mold attaching or detaching method described above, the mold halves are manually pushed into the plunger sleeves of the die plates and drawn off therefrom by workmen, and the mold clamping means has to be also manually adjusted. Such manual works require much time and labor for workmen, even if they are experts in the field. Particularly, in a large injection molding machine, it is a serious problem to eliminate workmen's labor and reduce their working time.
Moreover, since mold halves having various sizes are to be used for an injection molding machine depending upon the size and shape of products to be molded and the number of the products, the apparatus for detachably mounting the mold halves are required to be provided with a follow-up mechanism for the mold halves so as to attach or detach the mold halves of different size to or from a stationary and movable die plates. In the prior art, in order to solve this problem there has been proposed a method wherein the apparatus for detachably mounting the mold halves is disposed between the stationary and movable die plates with the apparatus fully opened to ensure a space for accommodating mold halves having various sizes when the mold halves are attached to the stationary and movable die plates. In this state, the apparatus clamps the mold halves and then the apparatus is moved to a position where the mold halves are clamped thereby to attach the mold halves to the stationary and movable die plates, respectively. When it is required to detach the mold halves from the stationary and movable die plates, the mold clamping means are released and the mold attaching-detaching apparatus are backwardly moved with the apparatus fully opened, thus detaching the mold halves from the respective die plates. In addition, it is required for the apparatus to maintain mold clamping force even in a case where a drive mechanism of the clamping means is stopped so as not to cause to fall down the mold halves secured to the stationary and movable die plate. However, for this purpose, the prior art mold attaching-detaching apparatus is provided independently with a drive mechanism for carrying out follow-up operation of the mold halves and a drive mechanism for clamping the mold halves. Such apparatus not only complicates the construction thereof but also occupies considerably wide space for attachment.